Recent advances in biotechnology made proteins and proteases of the extra cellular matrix of enamel available and facilitate the study of their function in-vitro as well as allowing the first attempts to synthesize this calcified tissue in an artificial environment. The overall objective of the current proposal is to determine the physical-chemical conditions required for a protein-guided development of a material that is comparable to the composition, structure and properties of human enamel. This work should lead to an improved understanding of how amelogenin proteins, the spliced variant LRAP+ and two proteases function in the biomineralization process on an ionic and molecular level and how this information can be used to synthesize enamel in-vitro. The hypothesis to be tested is that a biomimetic synthesis of thin layers of an enamel-like material, including composition, microstructure and properties is feasible by the use of full-length and spliced human amelogenins, when combined with selected proteases in mineralizing solutions at specific physical-chemical conditions. This hypothesis will be tested by the following three specific aims: (1) To determine the physical-chemical conditions that promote biomineralization mediated by full-length amelogenin and the spliced variant LRAP+; (2) To determine if amelogenin-induced biomineralization depends on the crystallographic orientation of the apatite substrate; and (3) To synthesize an enamel-like material by gradually degrading the amelogenin matrix using recombinant MMP-20 and serine proteinase while mineralization proceeds.